This pipe is large diameter round stock, hot rolled and galvanized for water carrying work. The zinc is applied to the pipe rather than left to a coating on site, so the outside, the bore and the cut ends are protected on a run that will be buried, clipped to a structure or left in the open. It is used for farm water mains, for irrigation supply lines and for structural pipework, and the same stock goes into the frames we supply so a site can work from one grade.
Water pipe on a farm is judged by what it looks like after ten years in the ground, not by what it looks like on the lorry. Large diameter galvanized pipe carries the volume a block needs without a pump working against a narrow line, and the coating is what decides whether the run is still sound when the joints are opened again.
A larger bore moves the same volume at a lower velocity, which reduces the pressure lost along the run. On a farm that matters at the far end of the block: a line that is sized too small will deliver at the headland and fall away over distance, so the last section is watered at a different rate from the first. This is the reason main lines are specified in a larger diameter than the lines that feed from them.
The same stock does structural work as well. Large diameter round pipe is used for shelter frames, for gate and fence structures and for the heavier members of a greenhouse frame, so a site can carry one grade and use it for both. Frames built from this stock are shown on the film greenhouse range page on this site, and the tube stock used for the lighter members is described in the heavy duty pre galvanized steel tube.
Galvanizing is done on the pipe, so the zinc covers the outside wall and the bore rather than only the face that can be reached with a brush. On a water line the inside is the surface that matters, because that is where the pipe is permanently wet, and it is the surface a site-applied coating cannot reach at all.
On the outside, the coating does the work at the two places a buried run fails first: at the joint, and where the pipe passes through a wall or a concrete apron. Cut ends and threaded ends expose bare steel, so they are treated at the time the pipe is cut rather than after the trench is backfilled.
The pipe is supplied to be worked on site. It can be cut to length, threaded for a screwed joint, welded, or connected with a mechanical coupling depending on the run and on how much of it will ever need to come apart. On a farm main, couplings and threaded joints are usually preferred because a section can be opened for a repair without cutting the line.
Two points are worth holding to. A cut end and a threaded end both need treating before they go into the ground, and welding burns the coating back along the pipe, so welded joints are the ones to inspect at the first season check. Where the pipe is being handled into a trench, slings rather than forks keep the coating intact on the underside. The pipe that carries the same grade into a greenhouse frame is described in the ASTM A53 galvanized pipe for greenhouse frames.
The table below is the standard stock. Diameter, wall thickness and length are set to the drawing.
| Type | Round |
| Standard | ASTM |
| Technique | Hot rolled |
| Surface treatment | Galvanized |
| Alloy or not | Non-alloy |
| Shape | Round bar stock |
| Jointing | Threaded, welded or mechanical coupling |
| Uses | Farm water mains, irrigation supply lines and structural frames |
| Delivery time | Set out in the quotation for each order |
Large diameter pipe is delivered in bundles, so unloading and stacking are part of the job. Bundles are lifted with slings wherever the site allows it, because a fork that slides under a bundle drags the coating off the bottom layer, and the coating is the reason the pipe was bought galvanized.
On site the stock should be kept off the ground on bearers and covered, so water does not sit inside the pipe ends through the wet season. Where a run is being laid, the pipe should be strung along the trench before it is jointed, so the joints are made once rather than remade after a section has been dragged into place.
This pipe is used for farm water mains and irrigation supply lines, for culverts and drainage runs, and for structural work such as shelter frames and greenhouse members. It suits farms laying a main to a block, contractors who need one grade of pipe across a site, and operations that want a line they can open for repair rather than replace.
Standards for steel products and for the coating systems applied to them are published by ASTM International. Reporting and analysis on agriculture and controlled environment growing is published by VerticalFarmDaily. The specification that matters is the one that still suits the job ten years from now.
Because a larger bore moves the same volume at a lower velocity and loses less pressure along the run. A line sized too small will deliver at the headland and fall away over distance, so the last section of the block is watered at a different rate.
The bore. Galvanizing is applied to the pipe itself, so the inside wall is coated, and the inside is permanently wet on a water line and out of reach of anything applied after installation.
A galvanized steel water line is rated for 15 to 20 years under normal conditions, with joints and any cut or threaded ends checked as part of the season service.
We provide a 10 year structural warranty and a 5 year anti-corrosion warranty on the galvanized steel. Details are set out in the contract for each project.
Send the diameters, wall thicknesses and quantities you need along with the application and the delivery port. We reply with a quotation and the delivery schedule.
